what is linux?

Question

can some one explain to me what is linux/unix?
i researched the net but i didn't find any explanation that i can understand...

Answer 1

Linux (IPA pronunciation: /ˈlɪnʊks/) is a Unix-like computer operating system family, as well as one of the most prominent examples of free software and open source development; its underlying source code can be modified, used, and redistributed by anyone, freely.[1]

After the Linux kernel was released to the public on 17 September 1991, the first Linux systems were completed by combining the kernel with system utilities and libraries from the GNU project, which led to the coining of the term GNU/Linux.[2] From the late 1990s onward Linux gained the support of corporations such as IBM,[3] Sun Microsystems,[4] Hewlett-Packard,[5] and Novell.[6]

Predominantly known for its use in servers, Linux recieves use as an operating system for a wider variety of computer hardware than any other operating system, including desktop computers, supercomputers,[7] mainframes, and embedded devices such as cellphones. Linux is packaged for different uses in Linux distributions, which contain the kernel along with a variety of other software packages tailored to requirements.

In 1991, Linus Torvalds began to work on the Linux kernel while he was attending the University of Helsinki.[8] Torvalds originally intended Linux to be a non-commercial replacement for Minix, an educational operating system developed by Andrew S. Tanenbaum.[9] Linux was dependent on the Minix userspace at first.

Richard Stallman, founder of the GNU project for a free operating system.

The GNU Project, with the goal of creating a UNIX-like, POSIX-compatible operating system composed entirely of free software,[10] had begun development in 1984, and a year later Richard Stallman had created the Free Software Foundation and wrote the first draft of the GNU General Public License (GPLv1). By the early 1990s, the project had produced or collected many necessary operating system components, including libraries, compilers, text editors, and a Unix shell, and the upper level could be supplied by the X Window System, but development of the lower level, which consisted of a kernel, device drivers and daemons had stalled and was incomplete.[11]

Code licensed under the GNU GPL can be used in other projects, so long as they too are released under the GPL. In order to make the Linux kernel compatible with the components from the GNU project, Torvalds changed his original license (which prohibited commercial redistribution) to the GPLv2.[12] Linux and GNU developers worked to integrate GNU components with Linux. Thus Linux became a complete, fully functional free operating system.

The Free Software Foundation views Linux distributions which use GNU software as "variants" of the GNU system, and they ask that such operating systems be referred to as GNU/Linux or a Linux-based GNU system.[18] However, the media and population at large refers to this family of operating systems simply as Linux. While some distributors make a point of using the aggregate form, most notably Debian with the Debian GNU/Linux distribution, its use outside of the enthusiast community is limited. The distinction between the Linux kernel and distributions based on it plus the GNU system is a source of confusion to many newcomers, and the naming remains controversial.

The Linux kernel and most GNU software are licensed under the GNU General Public License (GPL), version 2. The GPL requires that all distributed source code modifications and derived works also be licensed under the GPL, and is sometimes referred to as a "share and share-alike", "copyleft", or, pejoratively, a viral license. In 1997, Linus Torvalds stated, "Making Linux GPL'd was definitely the best thing I ever did."[19] Other software may use other licenses; many libraries use the GNU Lesser General Public License (LGPL), a more permissive variant of the GPL, and the X Window System uses the MIT License. After more than ten years, the Free Software Foundation announced that they would be upgrading the GPL to version 3, citing increasing concerns with software patents and digital rights management (DRM).[20] In particular, DRM is appearing in systems running copyleft software, a phenomenon dubbed "tivoization" after digital video recorder maker Tivo's use of DRM in their Linux-based appliances.[21] Linus Torvalds has publicly stated on the Linux Kernel Mailing List that, based on the drafts of the license, he would not move the Linux kernel to GPL v.3, specifically citing the DRM provisions.[22][23]

In March 2003, the SCO Group filed a lawsuit against IBM, claiming that IBM had contributed parts of SCO's copyrighted code to the Linux kernel, violating IBM's license to use Unix. Also, SCO sent letters to several companies warning that their use of Linux without a license from SCO may be actionable, and claimed in the press that they would be suing individual Linux users. Per the Utah District Court ruling on July 3, 2006; 182 out of 294 items of evidence provided by SCO against IBM in discovery were dismissed.[24]
See also: SCO-Linux controversies

In 2004, Ken Brown, president of the Alexis de Tocqueville Institution, published Samizdat, a highly controversial book which, among other criticism of open source software, denied Torvalds' authorship of the Linux kernel (attributing it to Tanenbaum, instead). This was rebutted by Tanenbaum himself.[25][26]

In the United States, the name Linux is a trademark registered to Linus Torvalds.[27] Initially, nobody registered it, but on August 15, 1994, William R. Della Croce, Jr. filed for the trademark Linux, and then demanded royalties from Linux distributors. In 1996, Torvalds and some affected organizations sued to have the trademark assigned to Torvalds, and in 1997 the case was settled.[28] The licensing of the trademark has since been handled by the Linux Mark Institute. Torvalds has stated that he only trademarked the name to prevent someone else from using it, but was bound in 2005 by United States trademark law to take active measures to enforce the trademark. As a result, the LMI sent out a number of letters to distribution vendors requesting that a fee be paid for the use of the name, and a number of companies have complied.

The Linux and GNU foundation formed the basis for an operating system which has since been completed by the efforts of numerous members of the free and open source software community. Significant milestones include:
The launch of the KDE desktop environment by Matthias Ettrich in October 1996[30] followed by the comparable GNOME alternative by Miguel de Icaza in August 1997,[31] both based on the X11 windowing system developed at MIT. GNOME and KDE became Linux operating system shells, responsible for the direct contact with users.
The release of the Netscape browser's source code on March 31, 1998, which kicked off the Mozilla project that would eventually give birth to the popular Mozilla Firefox browser.[32]

OpenOffice.org 2.2 - Writer : Word processor component of the multi-platform free software office suite.
The release of StarOffice by Sun Microsystems which in June 2000 became the base for the free software OpenOffice.org office suite,[33] a major event in the open source office world.[34] See also: list of free software.
The growth of commercial interest in Linux is similarly marked by notable events: the launch in February 1998 of the Open Source Initiative; the announcement in July 1998 by Oracle Corporation that it would port its well-known database software to Linux and provide support for it; the IPOs of Red Hat on November 11, 1999 and VA Linux the following month which would create a speculative bubble; the wide-scale support of technology giant IBM that would spend millions of dollars on Linux, employing in 2005 close to 300 developers of the Linux kernel, and would organize starting in 2003 the legal defense for the SCO vs. Linux controversy against the attacks of the SCO Group that claimed copyright over the Linux kernel; and finally the acquisition in October and November 2003 of Ximian and then SuSE by the American technology company Novell.[35]

Today Linux is used in numerous domains, from embedded systems[36] to supercomputers,[37] and has secured a place in server installations with the popular LAMP application stack.[38] Torvalds continues to direct the development of the kernel. Stallman heads the Free Software Foundation, which in turn develops the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries. Linux vendors combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions.

A 2001 study of Red Hat Linux 7.1 found that this distribution contained 30 million source lines of code. Using the Constructive Cost Model, the study estimated that this distribution required about eight thousand man-years of development time. According to the study, if all this software had been developed by conventional proprietary means, it would have cost about 1.08 billion dollars (year 2000 U.S. dollars) to develop in the United States.[39]

Most of the code (71%) was written in the C programming language, but many other languages were used, including C++, Lisp, assembly language, Perl, Fortran, Python and various shell scripting languages. Slightly over half of all lines of code were licensed under the GPL. The Linux kernel itself was 2.4 million lines of code, or 8% of the total.[39]

In a later study, the same analysis was performed for Debian GNU/Linux version 2.2.[40] This distribution contained over fifty-five million source lines of code, and the study estimated that it would have cost 1.9 billion dollars (year 2000 U.S. dollars) to develop by conventional means.

Most Linux distributions support dozens of programming languages. Core system software such as libraries and basic utilities are usually written in C. Enterprise software is often written in C, C++, Java, Perl, Ruby, or Python[citation needed]. The most common collection of utilities for building both Linux applications and operating system programs is found within the GNU toolchain, which includes the GNU Compiler Collection (GCC) and the GNU build system. Amongst others, GCC provides compilers for C, C++, Java, and Fortran. The Linux kernel itself is written to be compiled with GCC.

Most distributions also include support for Perl, Ruby, Python and other dynamic languages. Examples of languages that are less common, but still well-supported, are C# via the Mono project, and Scheme. A number of Java Virtual Machines and development kits run on Linux, including the original Sun Microsystems JVM (HotSpot), and IBM's J2SE RE, as well as many open-source projects like Kaffe. The two main frameworks for developing graphical applications are those of GNOME and KDE. These projects are based on the GTK+ and Qt widget toolkits, respectively, which can also be used independently of the larger framework. Both support a wide variety of languages. There are a number of Integrated development environments available including Anjuta, Eclipse, KDevelop, MonoDevelop, NetBeans, and Omnis Studio while the traditional editors Vim and Emacs remain popular.[41]

Although free and open source compilers and tools are widely used under Linux, there are also proprietary solutions available from a range of companies, including the Intel C++ Compiler, PathScale,[42] Micro Focus COBOL,[43] Franz Inc,[44] and the Portland Group.[45]

Linux is a widely ported operating system. While the Linux kernel was originally designed only for Intel 80386 microprocessors, it now runs on a more diverse range of computer architectures than any other operating system—[50] from the hand-held ARM-based iPAQ to the mainframe IBM System z9, in devices ranging from supercomputers to mobile phones. Specialized distributions exist for less mainstream architectures. The ELKS kernel fork can run on Intel 8086 or Intel 80286 16-bit microprocessors, while the µClinux kernel may run on systems without a memory management unit including the Apple iPod. The kernel also runs on architectures that were only ever intended to use a manufacturer-created operating system, such as the iMac and PowerBook, Palm PDAs, GameCube, Xbox, Playstation 3 and even the Playstation Portable.

Linux is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, Debian being a well-known example. Others maintain a community version of their commercial distributions, as RedHat does with Fedora Core.

In many cities and regions, local associations known as Linux Users Groups (LUGs) seek to promote Linux and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. There are also many internet communities that seek to provide support to Linux users and developers. Most distributions and open source projects have a chatroom on the popular freenode IRC network that are open to anybody with an IRC client. Online forums are another means for support, with notable examples being LinuxQuestions.org and the Gentoo forums. Finally, every established free software project and Linux distribution has one or more mailing lists; commonly there will be a specific topic such as usage or development for a given list. The Linux Kernel Mailing List is a high-volume list where all Linux kernel development happens. SourceForge, Savannah, and Apache host many free and open source software projects using standard collaborative software.

Linux-based newsgroups are available via the Google Groups interface and also via news readers. There are also several technology websites with a Linux focus. Linux Weekly News is a weekly digest of Linux-related news; the Linux Journal is an online magazine of Linux articles published monthly; Slashdot is a technology-related news website with many stories on Linux and open source software; Groklaw has written in depth about Linux-related legal proceedings; and there are many articles relevant to Linux on the Free Software Foundation website.

People who contribute to free software are not all software developers, as exemplified by the GNOME and KDE projects; there are many non-development contributions needed, as is the case for any software product. Furthermore, the principles of free software and open source have had repercussions in other domains where collaboration is possible and the cost of making copies is marginal. Amongst the members of this open source culture are the Creative Commons movement initiated by Lawrence Lessig and the collaborative encyclopedia Wikipedia founded by Jimmy Wales.

Although Linux is generally available free of charge, several large corporations have established business models that involve selling, supporting, and contributing to Linux and free software. These include IBM, HP, Sun Microsystems, Novell, and Red Hat. The free software licenses on which Linux is based explicitly accommodate and encourage commercialization; the relationship between Linux as a whole and individual vendors may be seen as symbiotic. One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer a specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks. Another business model is to give away the software in order to sell hardware.

The XO laptop project of One Laptop Per Child is creating a new and potentially much larger Linux community, planned to reach several hundred million schoolchildren and their families and communities in developing countries. Six countries have ordered a million or more units each for delivery in 2007 to distribute to schoolchildren at no charge. Google, Red Hat, and eBay are major supporters of the project.

Free software projects, although developed in a collaborative fashion, are often produced independently of each other. However, given that the software licenses explicitly permit redistribution, this provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution.

A Linux distribution, commonly called a "distro", is a project that manages a remote collection of Linux-based software, and facilitates installation of a Linux operating system. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. They include system software and application software in the form of packages, and distribution-specific software for initial system installation and configuration as well as later package upgrades and installs. A distribution is responsible for the default configuration of installed Linux systems, system security, and more generally integration of the different software packages into a coherent whole.

A typical general purpose distribution includes the following:
A boot loader: A piece of software that can be loaded by the systems firmware (bios in the case of a PC) and then perform the actions needed to load and start the linux kernel. Often a menu is presented that will allow the user to select which operating system to load. The most common bootloaders for the PC architecture are LILO or GRUB.
The Linux kernel: The core or heart of the operating system. The name of the OS comes from here.
Boot scripts, disk/storage maintenance tools, authentication tools, and scripting languages: They are administration tools, usually considered part of the operating system.
GNU C Library and, optionally, the GNU Compiler Collection: The development tools, used to assist or develop applications.
GNU bash shell, X Window System networking and display protocol and an accompanying desktop environment such as KDE, GNOME,or Xfce: The shells and graphic systems, used for interacting with the user.
Application software packages: There are hundreds of them in most distributions (thousands in bigger distributions, like Gentoo, Fedora, Debian, etc.) , from office suites to webservers to media players to 3D computer graphics software to text editors, and scientific programs. They may come in some storage medium, like a DVD, or, more commonly, be available in on-line repositories.
Package management software: These are created specifically for the distribution, for organizing all software, seamless downloading and installing, upgrading and managing security issues.

As well as those designed for general purpose use, distributions may be specialized for different purposes including: computer architecture support, embedded systems, stability, security, localization to a specific region or language, targeting of specific user groups, support for real-time applications, or commitment to a given desktop environment. Furthermore, some distributions deliberately include only free software. Currently, over three hundred distributions are actively developed, with about a dozen distributions being most popular for general-purpose use.

Under Linux, desktop software of high quality is in high demand; this includes applications such as word processors, spreadsheets, email clients, and web browsers. The following are the major Linux desktop applications:
Office: OpenOffice.org. It may be useful to compare office suites.
Internet: Firefox, Thunderbird, Evolution, Pidgin, and Azureus
Multimedia: VLC, MPlayer, Xine, XMMS, Totem, and Amarok
Graphics: The GIMP, Inkscape, Scribus, Blender

Although in specialized application domains such as desktop publishing and professional audio there may be a lack of commercial quality software, users migrating from Mac OS X and Windows can find equivalent applications for most tasks.[52] Furthermore, it is uncommon[citation needed] for a free software project that works under Windows or Mac OS X not to have a Linux version; a user accustomed to using free software under Windows can generally expect to find the same applications running under Linux.[citation needed] A growing amount of proprietary desktop software is also supported under Linux,[53] examples being Adobe Flash Player, Acrobat Reader, Nero Burning ROM, Opera, RealPlayer, and Skype. In the field of animation and visual effects, most highend software, such as AutoDesk Maya, Softimage XSI and Apple Shake are available both for Linux, Windows and/or MacOS X. Additionally, Crossover Office is a commercial solution based on the open source WINE project that supports running Windows versions of Microsoft Office and Photoshop.

There are far fewer games available for Linux than for Windows, console systems, or Mac OS X; game development companies generally receive a lower return on investment when they support an operating system with a small market share. The Linux Gamers' Game List is a long but selective list,[54] and The Linux Game Tome is a database with many entries that is less discriminating but has user comments and rankings.[55]

There are few original open source games that have obtained notability, examples being NetHack and Tux Racer. Remakes and re-releases are more common, examples being Freeciv and The Ur-Quan Masters. In some cases, developers have released Linux ports of their games directly, with id Software releasing both Quake 3 Arena and Quake 4. Independent companies have also taken on the task of porting prominent Windows games to Linux after their initial release. Loki Software was the first such company, founded in 1998, and superseded by Linux Game Publishing in 2001. Wine and the commercial Cedega fork allow many Windows games to run natively under Linux, and virtual machines and low-level machine emulators provide binary compatibility for games designed for other platforms.

Library support for Linux gaming is provided directly by OpenGL and ALSA, or by SDL, a cross-platform multimedia wrapper around system-dependent libraries. The DRI project provides open source video card drivers, and NVIDIA, and ATI also release binary kernel modules for their video cards. Linux runs on several game consoles, including the Xbox,[56] Playstation 2, 3, and GameCube,[57] which allows game developers without an expensive game development kit to access console hardware.

Additionally, some SEGA arcade machines, specifically the Sega Lindbergh series, run Linux. However, these machines have DRMs built in that prevent Linux users from running these games on other Linux machines.

Answer 2

Like someone else said, Linux is an operating system. If you've never used an operating system besides Windows, it is hard to imagine. Basically Linux is a competitor to Windows, one major difference being that Windows is expensive and Linux is usually free. Windows is designed and maintained by a dedicated team of people at Microsoft, whereas Linux is built by thousands of assorted people all over the Internet, volunteering their programming efforts toward a common cause. Windows is proprietary and standard, with closed source code and many secrets hiding in the registry. Linux is wild and non-standardized, with open source and countless distributions or versions available. Windows is fairly consistent from release to release, but Linux varies tremendously. Just because you know how to use one version of Linux (e.g. Fedora Core) does not mean you know how to use other versions of Linux (e.g. OpenBSD).

Linux is built on an older text-only operating system called UNIX. Linux usually adds GUI capabilities that allow you to use a mouse. A popular version today is Ubuntu Linux, which is easier to use than many older versions. Linux and its underlying UNIX functionality can be extremely cryptic and difficult to use, even for people like me - and I just graduated from an engineering school with a bachelor's degree in Computer Science! However, Linux is highly revered as being more stable and reliable than Windows. Linux is widely used in corporate environments for mission-critical systems which may run for years without needing reboots. The power and versatility of a Linux system in the proper administrative hands are unparalled by Windows.

I hope that helps!

Answer 3

Linux is a free open-source operating system based on Unix. Linux was originally created by Linus Torvalds with the assistance of developers from around the globe.

A freeware version of Unix, Linux is becoming popular as a powerful, low-cost operating system for running servers.

Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world. Developed under the GNU General Public License , the source code for Linux is freely available to everyone.

Linux is an open source operating system within the Unix family. Because of its robustness and availability, Linux has won popularity in the open source community and among commercial application developers.

Linux is a UNIX-like operating system that was designed to provide personal computer users a free or very low-cost operating system comparable to traditional and usually more expensive UNIX systems. Linux has a reputation as a very efficient and fast-performing system.

Answer 4

Well, in simple language, linux is another operating system like windows. Similar to the versions of windows (like Windows 98, XP, Vista etc.), there are many 50+ distributions(versions) of linux. Some of the popular ones are Ubuntu, Fedora Core, Red Hat, SUSE, FreeBSD etc.

All the linux distributions are free for personal use, while some, like Red Hat, are paid for enterprise use. Linux is open source - in the sense, any programmer can modify it and make a new version.

Though linux is powerful and great for servers and programming usage, I would recommend Windows for non geeks because linux needs you to remember many commands and is not so user friendly. You can get into a mess if you dont know what you are doing.

- Hope this helps you

PS: Executables(.exe) files cannot run on linux :(, so its really safe from viruses, thereby preffered for business and commercial use :)

Answer 5

Linux is just a kernal.
There are many more distributions based on Linux kernal called Linux Operating systems. like Fedora, Ubuntu..

Answer 6

linux is the core, the central common part, of numerous operating systems used for desktop,laptop, servers, mobile phones and a lot of high technology gadgets.

Some popular mainstream Linux distributions include Debian, Ubuntu, Linux Mint, Fedora, openSUSE, Arch Linux, there are also different commercial versions like Red Hat Enterprise Linux and SUSE Linux Enterprise Server, which are used in business and government.

Answer 7

Linux is a operating system under the name of (open source)
It's like windows and mac.

It's a pretty interesting thing to see.

Look here it's a video Windows Vista vs Linux & Add-on :
http://www.youtube.com/watch?v=xC5uEe5OzNQ

For more info look here :
http://en.wikipedia.org/wiki/Linux

Lot's of other operating system use Linux at the base.
http://en.wikipedia.org/wiki/List_of_Linux_distributions

But even if Linux is really really great. You should not go on it until you are good in computer. Because some softwares (80% of softwares) are not compatible. You can do thing to make it compatible but you need to know what you are doing.

Good Luck!

Answer 8

its an operating system like windows xp. Linux is an open source application meaning it is totally free. you can update anytime without having you pay extra. linux has different version there is Red Hat Linux, Linux Fedora, Linux Ubunto etc. Linux offers a great graphics on your pc without any video cards attached to it.

in a very short sentenced "Linux is a TREAT to windows"

Answer 9

Linux is an operating system like windows.

Answer 10

as windows is a operating system,

similarly, linux and unix are also operating system which is the interface to make u use up the computer.

Answer 11

Linux is a open source operating system modelled on unix. It is the software on a computer that enables applications and the computer operator to access the devices on the computer to perform desired functions. The operating system relays instructions from an application to, for instance, the computer's processor. The processor performs the instructed task, then sends the results back to the application via the operating system.
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